CircNSD1 promotes cardiac fibrosis through targeting the miR-429-3p/SULF1/Wnt/ß-catenin signaling pathway.

Cardiac fibrosis is a detrimental pathological process, which constitutes the key factor for adverse cardiac structural remodeling leading to heart failure and other critical conditions. Circular RNAs (circRNAs) have emerged as important regulators of various cardiovascular diseases. It is known that several circRNAs regulate gene expression and pathological processes by binding miRNAs. In this study we investigated whether a novel circRNA, named circNSD1, and miR-429-3p formed an axis that controls cardiac fibrosis. We established a mouse model of myocardial infarction (MI) for in vivo studies and a cellular model of cardiac fibrogenesis in primary cultured mouse cardiac fibroblasts treated with TGF-ß1. We showed that miR-429-3p was markedly downregulated in the cardiac fibrosis models. Through gain- and loss-of-function studies we confirmed miR-429-3p as a negative regulator of cardiac fibrosis. In searching for the upstream regulator of miR-429-3p, we identified circNSD1 that we subsequently demonstrated as an endogenous sponge of miR-429-3p. In MI mice, knockdown of circNSD1 alleviated cardiac fibrosis. Moreover, silence of human circNSD1 suppressed the proliferation and collagen production in human cardiac fibroblasts in vitro. We revealed that circNSD1 directly bound miR-429-3p, thereby upregulating SULF1 expression and activating the Wnt/ß-catenin pathway. Collectively, circNSD1 may be a novel target for the treatment of cardiac fibrosis and associated cardiac disease.

LncRNA-6395 promotes myocardial ischemia-reperfusion injury in mice through increasing p53 pathway.

Myocardial ischemia-reperfusion (I/R) injury is a pathological process characterized by cardiomyocyte apoptosis, which leads to cardiac dysfunction. Increasing evidence shows that abnormal expression of long noncoding RNAs (lncRNAs) plays a crucial role in cardiovascular diseases. In this study we investigated the role of lncRNAs in myocardial I/R injury. Myocardial I/R injury was induced in mice by ligating left anterior descending coronary artery for 45 min followed by reperfusion for 24 h. We showed that lncRNA KnowTID_00006395, termed lncRNA-6395 was significantly upregulated in the infarct area of mouse hearts following I/R injury as well as in H2O2-treated neonatal mouse ventricular cardiomyocytes (NMVCs). Overexpression of lncRNA-6395 led to cell apoptosis and the expression change of apoptosis-related proteins in NMVCs, whereas knockdown of lncRNA-6395 attenuated H2O2-induced cell apoptosis. LncRNA-6395 knockout mice (lncRNA-6395+/-) displayed improved cardiac function, decreased plasma LDH activity and infarct size following I/R injury. We demonstrated that lncRNA-6395 directly bound to p53, and increased the abundance of p53 protein through inhibiting ubiquitination-mediated p53 degradation and thereby facilitated p53 translocation to the nucleus. More importantly, overexpression of p53 canceled the inhibitory effects of lncRNA-6395 knockdown on cardiomyocyte apoptosis, whereas knockdown of p53 counteracted the apoptotic effects of lncRNA-6395 in cardiomyocytes. Taken together, lncRNA-6395 as an endogenous pro-apoptotic factor, regulates cardiomyocyte apoptosis and myocardial I/R injury by inhibiting degradation and promoting sub-cellular translocation of p53.

[CircRNA-0028171 regulates arsenic trioxide-induced apoptosis in vascular endothelial cells].

The present study was aimed to investigate the effects of circRNA-0028171 on the apoptosis of vascular endothelial cells induced by arsenic trioxide (As2O3). Human umbilical vein endothelial cells (HUVECs) were treated with 0-15 µmol/L As2O3 for 24 h. Then, cellular viability was measured by MTT assay. The expression levels of circRNA-0028171, Bcl-2 and Bax mRNA were detected by real-time quantitative PCR. Bcl-2/Bax protein ratio was detected by Western blot. Whether circRNA-0028171 was involved in the regulation of HUVECs by As2O3 was investigated by transfection with overexpression plasmid of circRNA-0028171 and siRNA. The results showed that compared with the control group, As2O3 group showed decreased cellular viability, reduced Bcl-2/Bax mRNA and protein ratios, and significantly lower expression of circRNA-0028171. Overexpression of circRNA-0028171 inhibited apoptosis of HUVECs induced by As2O3. Knockdown of circRNA-0028171 by siRNA promoted As2O3-induced apoptosis in HUVECs. These results suggest that circRNA-0028171 is involved in the vascular endothelial cell apoptosis induced by As2O3.

Anti-human serum albumin autoantibody may be involved in the pathogenesis of autoimmune bullous skin diseases.

Although effective immunological diagnostic systems for autoimmune bullous skin diseases (AIBD) have been established, there are still unidentified cutaneous autoantigens. The purpose of this study is to investigative whether anti-human serum albumin (HSA) autoantibodies exist in AIBD sera and their potential pathogenesis. By immunoprecipitation-immunoblotting, immunofluorescence assay, anti-HSA autoantibodies could be detected in AIBD sera; by ELISAs, positive rates of AIBD sera for IgG and IgA anti-HSA autoantibodies were 29% and 34%, respectively. The IgG anti-HSA autoantibodies in ABID sera recognized a number of HSA antigen epitopes and therefore a polyclonal antibody against HSA were next employed to study its pathogenesis. In vitro cell and tissue culture models, anti-HSA antibody could influence DNA damage-related signaling proteins, via activation of phospho-p38 signaling pathway. This is the first report that an autoantibody may influence DNA damage-related signaling proteins. Statistical analyses also proved that anti-HSA autoantibodies were positively correlated with various known autoantibodies and clinical features of ABID patients. In summary, IgG and IgA autoantibodies to HSA may have diagnosis values for AIBD. DNA damage-related signaling proteins might be involved in the pathogenic role of anti-HSA autoantibodies in AIBD. Phospho-p38 signaling pathway is a potential target for treatment of AIBD positive for serum anti-HSA autoantibodies.

Fibroblast growth factor 21 inhibited ischemic arrhythmias via targeting miR-143/EGR1 axis.

Ventricular arrhythmia is the most common cause of sudden cardiac death in patients with myocardial infarction (MI). Fibroblast growth factor 21 (FGF21) has been shown to play an important role in cardiovascular and metabolic diseases. However, the effects of FGF21 on ventricular arrhythmias following MI have not been addressed yet. The present study was conducted to investigate the pharmacological action of FGF21 on ventricular arrhythmias after MI. Adult male mice were administrated with or without recombinant human basic FGF21 (rhbFGF21), and the susceptibility to arrhythmias was assessed by programmed electrical stimulation and optical mapping techniques. Here, we found that rhbFGF21 administration reduced the occurrence of ventricular tachycardia (VT), improved epicardial conduction velocity and shorted action potential duration at 90% (APD90) in infarcted mouse hearts. Mechanistically, FGF21 may improve cardiac electrophysiological remodeling as characterized by the decrease of INa and IK1 current density in border zone of infarcted mouse hearts. Consistently, in vitro study also demonstrated that FGF21 may rescue oxidant stress-induced dysfunction of INa and IK1 currents in cultured ventricular myocytes. We further found that oxidant stress-induced down-regulation of early growth response protein 1 (EGR1) contributed to INa and IK1 reduction in post-infarcted hearts, and FGF21 may recruit EGR1 into the SCN5A and KCNJ2 promoter regions to up-regulate NaV1.5 and Kir2.1 expression at transcriptional level. Moreover, miR-143 was identified as upstream of EGR1 and mediated FGF21-induced EGR1 up-regulation in cardiomyocytes. Collectively, rhbFGF21 administration effectively suppressed ventricular arrhythmias in post-infarcted hearts by regulating miR-143-EGR1-NaV1.5/Kir2.1 axis, which provides novel therapeutic strategies for ischemic arrhythmias in clinics.

LncRNA ZFAS1 as a SERCA2a Inhibitor to Cause Intracellular Ca2+ Overload and Contractile Dysfunction in a Mouse Model of Myocardial Infarction.

RATIONALE: Ca2+ homeostasis-a critical determinant of cardiac contractile function-is critically regulated by SERCA2a (sarcoplasmic reticulum Ca2+-ATPase 2a). Our previous study has identified ZFAS1 as a new lncRNA biomarker of acute myocardial infarction (MI). OBJECTIVE: To evaluate the effects of ZFAS1 on SERCA2a and the associated Ca2+ homeostasis and cardiac contractile function in the setting of MI. METHODS AND RESULTS: ZFAS1 expression was robustly increased in cytoplasm and sarcoplasmic reticulum in a mouse model of MI and a cellular model of hypoxia. Knockdown of endogenous ZFAS1 by virus-mediated silencing shRNA partially abrogated the ischemia-induced contractile dysfunction. Overexpression of ZFAS1 in otherwise normal mice created similar impairment of cardiac function as that observed in MI mice. Moreover, at the cellular level, ZFAS1 overexpression weakened the contractility of cardiac muscles. At the subcellular level, ZFAS1 deleteriously altered the Ca2+ transient leading to intracellular Ca2+ overload in cardiomyocytes. At the molecular level, ZFAS1 was found to directly bind SERCA2a protein and to limit its activity, as well as to repress its expression. The effects of ZFAS1 were readily reversible on knockdown of this lncRNA. Notably, a sequence domain of ZFAS1 gene that is conserved across species mimicked the effects of the full-length ZFAS1. Mutation of this domain or application of an antisense fragment to this conserved region efficiently canceled out the deleterious actions of ZFAS1. ZFAS1 had no significant effects on other Ca2+-handling regulatory proteins. CONCLUSIONS: ZFAS1 is an endogenous SERCA2a inhibitor, acting by binding to SERCA2a protein to limit its intracellular level and inhibit its activity, and a contributor to the impairment of cardiac contractile function in MI. Therefore, anti-ZFAS1 might be considered as a new therapeutic strategy for preserving SERCA2a activity and cardiac function under pathological conditions of the heart.

Long non-coding RNA cardiac hypertrophy-associated regulator governs cardiac hypertrophy via regulating miR-20b and the downstream PTEN/AKT pathway.

Pathological cardiac hypertrophy (CH) is a key factor leading to heart failure and ultimately sudden death. Long non-coding RNAs (lncRNAs) are emerging as a new player in gene regulation relevant to a wide spectrum of human disease including cardiac disorders. Here, we characterize the role of a specific lncRNA named cardiac hypertrophy-associated regulator (CHAR) in CH and delineate the underlying signalling pathway. CHAR was found markedly down-regulated in both in vivo mouse model of cardiac hypertrophy induced by pressure overload and in vitro cellular model of cardiomyocyte hypertrophy induced by angiotensin II (AngII) insult. CHAR down-regulation alone was sufficient to induce hypertrophic phenotypes in healthy mice and neonatal rat ventricular cells (NRVCs). Overexpression of CHAR reduced the hypertrophic responses. CHAR was found to act as a competitive endogenous RNA (ceRNA) to down-regulate miR-20b that we established as a pro-hypertrophic miRNA. We experimentally established phosphatase and tensin homolog (PTEN), an anti-hypertrophic signalling molecule, as a target gene for miR-20b. We found that miR-20b induced CH by directly repressing PTEN expression and indirectly increasing AKT activity. Moreover, CHAR overexpression mitigated the repression of PTEN and activation of AKT by miR-20b, and as such, it abrogated the deleterious effects of miR-20b on CH. Collectively, this study characterized a new lncRNA CHAR and unravelled a new pro-hypertrophic signalling pathway: lncRNA-CHAR/miR-20b/PTEN/AKT. The findings therefore should improve our understanding of the cellular functionality and pathophysiological role of lncRNAs in the heart.

MicroRNA-92b-5p modulates melatonin-mediated osteogenic differentiation of bone marrow mesenchymal stem cells by targeting ICAM-1.

Osteoporosis is closely associated with the dysfunction of bone metabolism, which is caused by the imbalance between new bone formation and bone resorption. Osteogenic differentiation plays a vital role in maintaining the balance of bone microenvironment. The present study investigated whether melatonin participated in the osteogenic commitment of bone marrow mesenchymal stem cells (BMSCs) and further explored its underlying mechanisms. Our data showed that melatonin exhibited the capacity of regulating osteogenic differentiation of BMSCs, which was blocked by its membrane receptor inhibitor luzindole. Further study demonstrated that the expression of miR-92b-5p was up-regulated in BMSCs after administration of melatonin, and transfection of miR-92b-5p accelerated osteogenesis of BMSCs. In contrast, silence of miR-92b-5p inhibited the osteogenesis of BMSCs. The increase in osteoblast differentiation of BMSCs caused by melatonin was attenuated by miR-92b-5p AMO as well. Luciferase reporter assay, real-time qPCR analysis and western blot analysis confirmed that miR-92b-5p was involved in osteogenesis by directly targeting intracellular adhesion molecule-1 (ICAM-1). Melatonin improved the expression of miR-92b-5p, which could regulate the differentiation of BMSCs into osteoblasts by targeting ICAM-1. This study provided novel methods for treating osteoporosis.

Low-Intensity Pulsed Ultrasound Prevents the Oxidative Stress Induced Endothelial-Mesenchymal Transition in Human Aortic Endothelial Cells.

BACKGROUND/AIMS: Endothelial-mesenchymal transition (EndMT) has been shown to take part in the generation and progression of diverse diseases, involving a series of changes leading to a loss of their endothelial characteristics and an acquirement of properties typical of mesenchymal cells. Low-intensity pulsed ultrasound (LIPUS) is a new therapeutic option that has been successfully used in fracture healing. However, whether LIPUS can inhibit oxidative stress-induced endothelial cell damages through inhibiting EndMT remained unknown. This study aimed to investigate the protective effects of LIPUS against oxidative stress-induced endothelial cell damages and the underlying mechanisms. METHODS: EndMT was induced by H2O2 (100 µm for seven days). Human aortic endothelial cells (HAECs) were exposed to H2O2 with or without LIPUS treatment for seven days. The expression of EndMT markers (CD31, VE-cadherin, FSP1 and α-SMA) were analyzed. The levels of total and phosphorylated PI3K and AKT proteins were detected by Western Blot analysis. Cell chemotaxis was determined by wound healing and transwell assay. RESULTS: LIPUS relieved EndMT by decreasing ROS accumulation and increasing activation of the PI3K signaling cascade. LIPUS alleviated the migration of EndMT-derived mesenchymal-like cells through reducing extracellular matrix (ECM) deposition that is associated with matrix metallopeptidase (MMP) proteolytic activity and collagen production. CONCLUSION: LIPUS produces cytoprotective effects against oxidative injuries to endothelial cells through suppressing the oxidative stress-induced EndMT, activating the PI3K/AKT pathway under oxidative stress, and limiting cell migration and excessive ECM deposition.

Melatonin prevents endothelial cell pyroptosis via regulation of long noncoding RNA MEG3/miR-223/NLRP3 axis.

Atherosclerosis (AS) is an inflammatory disease linked to endothelial dysfunction. Melatonin is reported to possess substantial anti-inflammatory properties, which has proven to be effective in AS. Emerging literature suggests that pyroptosis plays a critical role during AS progression. However, whether pyroptosis contributes to endothelial dysfunction and the underlying molecular mechanisms remained unexploited. This study was designed to investigate the antipyroptotic effects of melatonin in atherosclerotic endothelium and to elucidate the potential mechanisms. In this study, high-fat diet (HFD)-treated ApoE-/- mice were used as an atherosclerotic animal model. We found intragastric administration of melatonin for 12 weeks markedly reduced the atherosclerotic plaque in aorta. Meanwhile, melatonin also attenuated the expression of pyroptosis-related genes, including NLRP3, ASC, cleaved caspase1, NF-κB/GSDMD, GSDMD N-termini, IL-1ß, and IL-18 in aortic endothelium of melatonin-treated animals. Consistent antipyroptotic effects were also observed in ox-LDL-treated human aortic endothelial cells (HAECs). We found that lncRNA MEG3 enhanced pyroptosis in HAECs. Moreover, MEG3 acted as an endogenous sponge by sequence complementarity to suppress the function of miR-223 and to increase NLRP3 expression and enhance endothelial cell pyroptosis. Furthermore, knockdown of miR-223 blocked the antipyroptotic actions of melatonin in ox-LDL-treated HAECs. Together, our results suggest that melatonin prevents endothelial cell pyroptosis via MEG3/miR-223/NLRP3 axis in atherosclerosis, and therefore, melatonin replacement might be considered a new strategy for protecting endothelium against pyroptosis, thereby for the treatment of atherosclerosis associated with pyroptosis.

Circulating long non-coding RNAs NRON and MHRT as novel predictive biomarkers of heart failure.

This study sought to evaluate the potential of circulating long non-coding RNAs (lncRNAs) as biomarkers for heart failure (HF). We measured the circulating levels of 13 individual lncRNAs which are known to be relevant to cardiovascular disease in the plasma samples from 72 HF patients and 60 non-HF control participants using real-time reverse transcription-polymerase chain reaction (real-time RT-PCR) methods. We found that out of the 13 lncRNAs tested, non-coding repressor of NFAT (NRON) and myosin heavy-chain-associated RNA transcripts (MHRT) had significantly higher plasma levels in HF than in non-HF subjects: 3.17 ± 0.30 versus 1.0 ± 0.07 for NRON (P < 0.0001) and 1.66 ± 0.14 versus 1.0 ± 0.12 for MHRT (P < 0.0001). The area under the ROC curve was 0.865 for NRON and 0.702 for MHRT. Univariate and multivariate analyses identified NRON and MHRT as independent predictors for HF. Spearman's rank correlation analysis showed that NRON was negatively correlated with HDL and positively correlated with LDH, whereas MHRT was positively correlated with AST and LDH. Hence, elevation of circulating NRON and MHRT predicts HF and may be considered as novel biomarkers of HF.

miR-106a promotes cardiac hypertrophy by targeting mitofusin 2.

Pathological cardiac hypertrophy is a main factor leading to heart failure and associated sudden death. Improved understanding of the underlying molecular mechanisms should aid better treatment of the disease. This study aimed to test our hypothesis that a microRNA miR-106a played an important role in the development of cardiac hypertrophy through targeting mitofusin 2 (Mfn2), a mitochondrial fusion protein known to be critical in regulating cardiac function. miR-106a was robustly upregulated in hypertrophied myocardium both in vivo and in vitro. Forced transient expression of miR-106a in otherwise healthy cardiomyocytes induced the hypertrophic phenotypes resembling those produced by angiotensin II (AngII) exposure. Knockdown of miR-106a by its specific inhibitor nearly completely reversed the hypertrophic phenotypes induced by AngII pretreatment and pressure overload. On the other hand, Mfn2 was markedly downregulated in hypertrophic heart and cardiomyocytes, which was in reciprocal to expression of miR-106a. Mfn2 was experimentally validated as a direct target gene for miR-106a. Overexpression of Mfn2 counteracted the hypertrophic responses induced by miR-106a, whereas silence of Mfn2 by its siRNA abolished the anti-hypertrophic property of miR-106a inhibitor. Furthermore, overexpression of Mfn2 alleviated the hypertrophic phenotypes induced by AngII in cultured cardiomyocytes, while Mfn2 siRNA alone was able to induce hypertrophic changes in cultured cardiomyocytes. Moreover, AngII and miR-106a treatment cultured cardiomyocytes mitochondria presented cristae defects, considerable depolarization of mitochondrial membrane and increased ROS production. These alterations were reversed by miR-106a inhibitor or overexpression of Mfn2. Taken together, our findings indicate miR-106a as an important factor to promote hypertrophic progress and suggest miR-106a as a new molecular target for the treatment of pathological hypertrophy. The present study also uncovered a novel relationship between miR-106a and Mfn2, with Mfn2 as a downstream signaling mediator of miR-106a.

Regulation of Insulin Resistance by Multiple MiRNAs via Targeting the GLUT4 Signalling Pathway.

BACKGROUND/AIMS: Type 2 Diabetes Mellitus (T2DM) is characterized by insulin resistance (IR), but the underlying molecular mechanisms are incompletely understood. MicroRNAs (miRNAs) have been demonstrated to participate in the signalling pathways relevant to glucose metabolism in IR. The purpose of this study was to test whether the multiple-target anti-miRNA antisense oligonucleotides (MTg-AMO) technology, an innovative miRNA knockdown strategy, can be used to interfere with multiple miRNAs that play critical roles in regulating IR. METHODS: An MTg-AMO carrying the antisense sequences targeting miR-106b, miR-27a and miR-30d was constructed (MTg-AMO106b/27a/30d). Protein levels were determined by Western blot analysis, and transcript levels were detected by real-time RT-PCR (qRT-PCR). Insulin resistance was analysed with glucose consumption and glucose uptake assays. RESULTS: We found that the protein level of glucose transporter 4 (GLUT4), Mitogen-activated protein kinase 14 (MAPK 14), Phosphatidylinositol 3-kinase regulatory subunit beta (PI3K regulatory subunit beta) and mRNA level of Slc2a4 (encode GLUT4), Mapk14 (encode MAPK 14) and Pik3r2 (encode PI3K regulatory subunit beta) were all significantly down-regulated in the skeletal muscle of diabetic rats and in insulin-resistant L6 cells. Overexpression of miR-106b, miR-27a and miR-30d in L6 cells decreased glucose consumption and glucose uptake, and reduced the expression of GLUT4, MAPK 14 and PI3K regulatory subunit beta. Conversely, silencing of endogenous miR-106b, miR-27a and miR-30d in insulin-resistant L6 cells enhanced glucose consumption and glucose uptake, and increased the expression of GLUT4, MAPK 14 and PI3K regulatory subunit beta. MTg-AMO106b/27a/30d up-regulated the protein levels of GLUT4, MAPK 14 and PI3K regulatory subunit beta, enhanced glucose consumption and glucose uptake. CONCLUSION: Our data suggested that miR-106b, miR-27a and miR-30d play crucial roles in the regulation of glucose metabolism by targeting the GLUT4 signalling pathway in L6 cells. Moreover, MTg-AMO106b/27a/30d offers more potent effects than regular singular AMOs.

MiR-223-3p as a Novel MicroRNA Regulator of Expression of Voltage-Gated K+ Channel Kv4.2 in Acute Myocardial Infarction.

BACKGROUND/AIMS: Acute myocardial infarction (AMI) is a devastating cardiovascular disease with a high rate of morbidity and mortality, partly due to enhanced arrhythmogenicity. MicroRNAs (miRNAs) have been shown to participate in the regulation of cardiac ion channels and the associated arrhythmias. The purpose of this study was to test our hypothesis that miR-223-3p contributes to the electrical disorders in AMI via modulating KCND2, the gene encoding voltage-gated channel Kv4.2 that carries transient outward K+ current Ito. METHODS: AMI model was established in male Sprague-Dawley (SD) rats by left anterior descending artery (LAD) ligation. Evans blue and TTC staining was used to measure infarct area. Ito was recorded in isolated ventricular cardiomyocytes or cultured neonatal rat ventricular cells (NRVCs) by whole-cell patch-clamp techniques. Western blot analysis was employed to detect the protein level of Kv4.2 and real-time RT-PCR to determine the transcript level of miR-223-3p. Luciferase assay was used to examine the interaction between miR-223-3p and KCND2 in cultured NRVCs. RESULTS: Expression of miR-223-3p was remarkably upregulated in AMI relative to sham control rats. On the contrary, the protein level of Kv4.2 and Ito density were significantly decreased in AMI. Consistently, transfection of miR-223-3p mimic markedly reduced Kv4.2 protein level and Ito current in cultured NRVCs. Co-transfection of AMO-223-3p (an antisense inhibitor of miR-223-3p) reversed the repressive effect of miR-223-3p. Luciferase assay showed that miR-223-3p, but not the negative control, substantially suppressed the luciferase activity, confirming the direct binding of miR-223-3p to the seed site within the KCND2 sequence. Finally, direct intramuscular injection of AMO-223-3p into the ischemic myocardium to knockdown endogenous miR-223-3p decreased the propensity of ischemic arrhythmias. CONCLUSIONS: Upregulation of miR-223-3p in AMI repressed the expression of KCND2/Kv4.2 resulting in reduction of Ito density that can cause APD prolongation and promote arrhythmias in AMI, and therefore knockdown of endogenous miR-223-3p might be considered a new approach for antiarrhythmic therapy of ischemic arrhythmias.

Suppression of AKT expression by miR-153 produced anti-tumor activity in lung cancer.

Lung cancer is one of the leading causes of cancer death worldwide. microRNAs have been shown to be a novel class of regulators in lung cancer. Here, we explored the role of miR-153 in the pathogenesis of lung cancer and its therapeutic potential. miR-153 was significantly decreased in lung cancer tissues than the adjacent tissues. The protein and mRNA levels of protein kinase B (AKT), which were shown to promote tumor growth, were both increased in lung cancer tissues than adjacent tissues. Overexpression of miR-153 significantly inhibited AKT protein expression, which were abrogated by co-transfection of AMO-153, the specific inhibitor of miR-153. Luciferase assay showed that transfection of miR-153 markedly suppressed the fluorescent intensity of chimeric vectors carrying the 3'UTR of AKT1, while produced no effect on the mutant construct, indicating that AKT is regulated by miR-153. Overexpression of miR-153 significantly inhibited the proliferation and migration, and promoted apoptosis of cultured lung cancer cells in vitro, and suppressed the growth of xenograft tumors in vivo. Interestingly, lung cancer cells with lower endogenous miR-153 expression are more sensitive to ectopic overexpressed miR-153. The IC50 of miR-153 on lung cancer cells is positive correlated with the endogenous miR-153 level, while negative correlated with AKT level. Knockdown of AKT expression suppressed lung cancer cell proliferation. In summary, miR-153 exerted anti-tumor activity in lung cancer by targeting on AKT. The sensitivity of lung cancer cells to miR-153 is determined by its endogenous miR-153 level.

The antifibrotic effects and mechanisms of microRNA-26a action in idiopathic pulmonary fibrosis.

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, and high-lethality fibrotic lung disease characterized by excessive fibroblast proliferation, extracellular matrix accumulation, and, ultimately, loss of lung function. Although dysregulation of some microRNAs (miRs) has been shown to play important roles in the pathophysiological processes of IPF, the role of miRs in fibrotic lung diseases is not well understood. In this study, we found downregulation of miR-26a in the lungs of mice with experimental pulmonary fibrosis and in IPF, which resulted in posttranscriptional derepression of connective tissue growth factor (CTGF), and induced collagen production. More importantly, inhibition of miR-26a in the lungs caused pulmonary fibrosis in vivo, whereas overexpression of miR-26a repressed transforming growth factor (TGF)-ß1-induced fibrogenesis in MRC-5 cells and attenuated experimental pulmonary fibrosis in mice. Our study showed that miR-26a was downregulated by TGF-ß1-mediated phosphorylation of Smad3. Moreover, miR-26a inhibited the nuclear translocation of p-Smad3 through directly targeting Smad4, which determines the nuclear translocation of p-Smad2/Smad3. Taken together, our experiments demonstrated the antifibrotic effects of miR-26a in fibrotic lung diseases and suggested a new strategy for the prevention and treatment of IPF using miR-26a. The current study also uncovered a novel positive feedback loop between miR-26a and p-Smad3, which is involved in pulmonary fibrosis.

ß-Blocker carvedilol protects cardiomyocytes against oxidative stress-induced apoptosis by up-regulating miR-133 expression.

Oxidative stress is a causal factor and key promoter of a variety of cardiovascular diseases associated with apoptotic cell death by causing deregulation of related genes. Though carvedilol, a ß-adrenergic blocker, has been shown to produce cytoprotective effects against cardiomyocyte apoptosis, the mechanisms are not fully understood. The present study was designed to investigate whether the beneficial effects of carvedilol are related to microRNAs which have emerged as critical players in cardiovascular pathophysiology via post-transcriptional regulation of protein-coding genes. In vivo, we demonstrated that carvedilol ameliorated impaired cardiac function of infarct rats and restored miR-133 expression. In vitro, carvedilol protected cardiomyocytes from H2O2 induced apoptosis detected by TUNEL staining and MTT assays, and increased miR-133 expression in cardiomyocytes. Overexpression of miR-133, a recognized anti-apoptotic miRNA, produced similar effects to carvedilol: reduction of reactive oxygen species (ROS) and malondialdehyde (MDA) content and increment of superoxide dismutase (SOD) activity and glutathione peroxidase (GPx) level, so as to protect cardiomyocytes from apoptosis by downregulating caspase-9 and caspase-3 expression in the presence of H2O2. Transfection with AMO-133 (antisense inhibitor oligodeoxyribonucleotides) alone abolished the beneficial effects of carvedilol. Caspase-9-specific inhibitor z-LEHD-fmk, caspase-3-specific inhibitor z-DEVD-fmk, caspase-9 siRNA and caspase-3 siRNA were used to establish caspase-3 as a downstream target of miR-133. In conclusion, our data indicated that carvedilol protected cardiomyocytes by increasing miR-133 expression and suppressing caspase-9 and subsequent apoptotic pathways.

let-7e replacement yields potent anti-arrhythmic efficacy via targeting beta 1-adrenergic receptor in rat heart.

Beta-adrenoceptor (ß-AR) exerts critical regulation of cardiac function. MicroRNAs (miRNAs) are potentially involved in a variety of biological and pathological processes. This study aimed to investigate the role of miRNA let-7e in the up-regulation of ß(1) -AR and arrhythmogenesis in acute myocardial infarction (AMI) in rats. ß(1) -AR expression was significantly up-regulated and let-7a, c, d, e and i were markedly down-regulated in the infarcted heart after 6 and 24 hrs myocardial infarction. Forced expression of let-7e suppressed ß(1) -AR expression at the protein level, without affecting ß(1) -AR mRNA level, in neonatal rat ventricular cells (NRVCs). Silencing of let-7e by let-7e antisense inhibitor (AMO-let-7e) enhanced ß(1) -AR expression at the protein level in NRVCs. Administration of the lentivirus vector containing precursor let-7e (len-pre-let-7e) significantly inhibited ß(1) -AR expression in rats, whereas len-AMO-let-7e up-regulated ß(1) -AR relative to the baseline control level, presumably as a result of depression of tonic inhibition of ß(1) -AR by endogenous let-7e. Len-negative control (len-NC) did not produce significant influence on ß(1) -AR expression. Len-pre-let-7e also profoundly reduced the up-regulation of ß(1) -AR induced by AMI and this effect was abolished by len-AMO-let-7e. Importantly, len-pre-let-7e application significantly reduced arrhythmia incidence after AMI in rats and its anti-arrhythmic effect was cancelled by len-AMO-let-7e. Notably, anti-arrhythmic efficacy of len-pre-let-7e was similar to propranolol, a non-selective ß-AR blocker and metoprolol, a selective ß(1) -AR blocker. Down-regulation of let-7e contributes to the adverse increase in ß(1) -AR expression in AMI and let-7e supplement may be a new therapeutic approach for preventing adverse ß(1) -AR up-regulation and treating AMI-induced arrhythmia.

miR-101 promotes breast cancer cell apoptosis by targeting Janus kinase 2.

AIMS: microRNA-101 (miR-101) is down-regulated in several cancers. In this study, we explored the effects of dysregulated miR-101 on breast cancer cells and the underlying mechanisms. METHODS: miR-101 level was quantified by real-time RT-PCR. Cell viability was analyzed by MTT assay. Apoptosis was detected by flow cytometry and TUNEL assay. Moreover, the level of protein expression was determined by Western blot. RESULTS: miR-101 level was markedly reduced in both the human breast cancer samples and cultured breast cancer cell lines (MCF-7, MDA-MB-231). Overexpression of miR-101 inhibited the proliferation and promoted the apoptosis in cultured MCF-7 and MDA-MB-231 cells, which were reversed by co-transfection of AMO-101, the inhibitor of miR-101. We validated Janus kinase 2 (Jak2) as a direct target of miR-101. Knockdown of Jak2 induced apoptosis in cultured breast cancer cells. Moreover, the level of miR-101 is negatively correlated with Jak2 in breast cancer tissues and cell lines. CONCLUSIONS: miR-101 suppressed proliferation and promoted apoptosis in breast cancer cells by targeting Jak2. These findings indicate that manipulation of miR-101 expression may represent a novel therapeutic strategy in the treatment of breast cancer.

By targeting Stat3 microRNA-17-5p promotes cardiomyocyte apoptosis in response to ischemia followed by reperfusion.

BACKGROUND: Several studies have confirmed the role of microRNAs in regulating ischemia/reperfusion-induced cardiac injury (I/R-I). MiR-17-5p has been regarded as an oncomiR in the development of cancer. However, its potential role in cardiomyocytes has not been exploited. The aim of this study is to investigate the role of miR-17-5p in I/R-I and the underlying mechanism through targeting Stat3, a key surviving factor in cardiomyocytes. METHODS: MTT (3-[4, 5-dimethylthiazol-2-yl]-2, 5 diphenyl tetrazolium bromide) assay was used to detect the cell viability. ELISA and TUNEL were performed to measure apoptosis of neonatal rat ventricular cardiomyocytes (NRVCs). Infarct area was estimated by TTC (triphenyltetrazolium chloride) and Evans blue staining. Western blot analysis was employed to detect the Stat3 and p-Stat3 levels and real-time RT-PCR was used to quantify miR-17-5p level. RESULTS: The miR-17-5p level was significantly up-regulated in I/R-I mice and in NRVCs under oxidative stress. Overexpression of miR-17-5p aggravated cardiomyocyte injury with reduced cell viability and enhanced apoptotic cell death induced by H2O2, whereas inhibition of miR-17-5p by its antisense AMO-17-5p abrogated the deleterious changes. Moreover, the locked nucleic acid-modified antisense (LNA-anti-miR-17-5p) markedly decreased the infarct area and apoptosis induced by I/R-I in mice. Furthermore, overexpression of miR-17-5p diminished the p-Stat3 level in response to H2O2. The results from Western blot analysis and luciferase reporter gene assay confirmed Stat3 as a target gene for miR-17-5p. CONCLUSION: Upregulation of miR-17-5p promotes apoptosis induced by oxidative stress via targeting Stat3, accounting partially for I/R-I.